A Ninja player of mine and I have been in debate about whether he is allowed extra sneak attacks after vanishing and using the Equipment Trick(Hurl Scabbard).

Hurl Scabbard (Quick Draw): You can draw your weapon in such a way that you send your combat scabbard (see page 3) whirling off to strike at any creature in sight. This ranged attack is a swift action and is treated as a thrown weapon.

Vanishing Trick (Su): As a swift action, the ninja can disappear for 1 round per level. This ability functions as invisibility. Using this ability uses up 1 ki point.

Our last session the Ninja moved, demoralized, then vanished, his following round he hurled his scabbard, then proceeded with his full-attack action. I only allowed him the sneak attack bonus to the scabbard, because I'm sure that's how it's supposed to work.

At the time I couldn't find the rule, and still now I can't seem to find where it specifically states that after the first attack, the target is then aware and allowed his Dex bonus again. Please help clarify that only the Scabbard gets the sneak attack bonus, and no other attacks.